The present invention relates to a method and an apparatus for correcting video signals in color printing simulation for determining or checking color separation conditions.
Color printing simulation apparatus of the type described above are quite convenient and are rapidly developing since proof-printing which requires much labor, time and cost can be eliminated or reduced.
One requirement of a printing simulation apparatus of this type is the optimal resemblance of the image on the color monitor to the printed image. In order to achieve such optimal resemblance, the present applicant proposed in Japanese Patent Application No. 5,625/1975 (Japanese Patent Publication No. 38,922/1979) a technique for better resemblance of particularly secondary and tertiary colors of the image on the color monitor to the printed image.
In general, a low under color removal (U.C.R.%) is adopted in Japan. With a low U.C.R.%, it is possible to achieve optimal approximation with the technique disclosed in the above-mentioned publication. However, a high U.C.R.% is adopted in the U.S.A. and European countries. With such a high U.C.R.%, satisfactory resemblance can not be achieved in practice by the technique disclosed in the above-mentioned publication.
Another requirement of an apparatus of this type is ease in preadjustment before operation.
The printing simulation apparatus must be preadjusted in accordance with the printing steps prior to actual simulation. For example, correction factors are adjusted so as to achieve optimal resemblance of an image on the color monitor to the printed image in accordance with the type of printing plate, type of plate making, kind of inks and paper and so on. This preadjustment requires a number of days. The reliability of operation of the printing simulation apparatus depends upon the ease and exactness of preadjustments like this.